Clearing the various conduits and chambers of a mobile spraying apparatus, such as on a vehicle which can be transported to remote locations for use, can often be difficult and time consuming. Such spraying apparatuses can be configured, for example, to dispense seed, bark, mulch, landfill cover, and/or a variety of other ingredients. Each such spraying apparatus typically includes a reservoir, a pump, a nozzle, and one or more conduits connecting the reservoir, the pump, and the nozzle. In some circumstances, after spraying material (e.g., a grass seed slurry), it is beneficial to purge the conduit(s), the nozzle, and/or the pump to prevent a buildup of material therein that could obstruct proper flow during the next use of the spraying apparatus or after repeated uses of the apparatus.
Water is often used to purge a vehicular spraying apparatus. However, unless the vehicle will always be cleaned in the vicinity of a water source (e.g., a pond, fire hydrant, or water faucet), the vehicle must include its own portable water source (i.e., a water tank) for use in such cleaning operations. Requiring a spraying apparatus to be located near a water source to enable purging is often not practical because it is generally most convenient to clean the spraying apparatus immediately after use. Furthermore, in the time it would take for a vehicle to travel to a water source, the material accumulated within the spraying apparatus can harden, and can therefore be resistant to purging. However, any sufficiently sized water tank associated with the vehicle would add a significant amount of weight, thereby requiring an oversized vehicle and/or a reduction in capacity for sprayable material. For these reasons, water is not an effective option for use in purging or cleaning a vehicular spraying apparatus.
Compressed air can also be used to purge components of a spraying apparatus. For example, when a spraying apparatus is associated with a large truck, the truck can include an engine-driven air compressor that generates compressed air for storage within a reservoir (e.g., typically for use by air brakes). Air from this reservoir can be directed into the spraying apparatus to evacuate various components thereof. However, many spraying apparatuses are often not associated with such large trucks, and smaller trucks and trailers typically do not include engine-driven air compressors. Installation of engine-driven air compressors on smaller trucks and trailers can be very expensive and time consuming. Also, when such an engine-driven air compressor is installed in this manner, it is typically necessary to additionally install an air tank, piping, and other related components, thereby further increasing costs, engineering time, and assembly time.
In lieu of an engine-driven air compressor, an air compressor can be provided to operate directly from a vehicle's low voltage direct current electrical system (e.g., commonly provided as 6 V.D.C., 12 V.D.C., or 24 V.D.C.) or from a vehicle's hydraulic system. However, such air compressors are typically extremely expensive, are difficult to source due to relatively low market availability, and can in many circumstances be unreliable due to lack of adequate robustness. Also, when such an air compressor is installed, it is typically necessary to additionally install an air tank, piping, and other related components, thereby further increasing costs, engineering time, and assembly time.
Accordingly, there is a need for an air flush system for a spraying apparatus that is relatively inexpensive, is easy to install, requires little engineering time, and is quite reliable.